HVAC-Talk site will be slow for the next few days. It's normal site/server maintenance. Thx -Dad

Welcome to HVAC-Talk.com, a non-DIY site and the ultimate Source for HVAC Information & Knowledge Sharing for the industry professional! Here you can join over 150,000 HVAC Professionals & enthusiasts from around the world discussing all things related to HVAC/R. You are currently viewing as a NON-REGISTERED guest which gives you limited access to view discussions

To gain full access to our forums you must register; for a free account. As a registered Guest you will be able to:

Participate in over 40 different forums and search/browse from nearly 3 million posts.

I don't know whay brand your cas is. Look online, i have seen them on structural concepts cases and many other brands. I will look as well to see what i can find. The usually call the "night curtains". Almost like a window shade but they usually have a slight perferation to them.

Open air cases will sometimes ice up at irregular intervals, based on when nearby HVAC Supply Air Ducts are 'washing out' the case air curtain. Especially when the HVAC is Calling for Heating. It's possible you don't have a Refrigeration problem.

The views and opinions posted here are my own. They do not reflect the corporate policies of my employer and will most likely get me fired at some point.

Open air cases will sometimes ice up at irregular intervals, based on when nearby HVAC Supply Air Ducts are 'washing out' the case air curtain. Especially when the HVAC is Calling for Heating. It's possible you don't have a Refrigeration problem.

Right, no sense in over analyzing this, it is a one time thing, and the coil defrosts just fine. Of course when you question was the door open the day of the freeze up, you just get a big NO? The customer is a great guy to work with, and he is all cool with it may be a fluke, and may happen again. Plus I get the sale of the night curtains on a 48', 12', and 36' case. So that will be some good money$$$$$$$$$$

[QUOTE=EugeneTheJeep;14760341
Drains run clear, verified by hot water defrost.[/QUOTE]

Did you confirm the P-trap is full of water and not allowing the influx of moisture laden air into the bottom of the case?
I have seen cracked P-traps leak out into the transit or underneath the case not visible unless you look behind the kickplate. Defrost water fills trap, trap leaks out in 30 minutes, reverse airflow from drain water venting pulls moisture into case
Some traps have a drainplug/cap on the bottom for cleanout. They can also leak there if not tight.

Did you confirm the P-trap is full of water and not allowing the influx of moisture laden air into the bottom of the case?
I have seen cracked P-traps leak out into the transit or underneath the case not visible unless you look behind the kickplate. Defrost water fills trap, trap leaks out in 30 minutes, reverse airflow from drain water venting pulls moisture into case
Some traps have a drainplug/cap on the bottom for cleanout. They can also leak there if not tight.

Just something extra to check...

That sounds like a good idea, however the case still is running fine. But it is something I will check next time. It only froze up that one balmy fall couple of days where it rained heavy?

Originally Posted by Snapperhead

This more than likely has a head master .... are you familiar with charging this kind of setup in winter ?

If someone worked on this unit during summer, and charged it by " sight glass " it would run fine all summer , but they didnt charge it properly for winter.

Been working in cold climate for 30 years, so it is not my first. The unit is charged to receiver capacity.